Intro to Hormone Physiology Flashcards
When the thyroid gland produces a hormone called T4, what happens?
Also known as Thyroxine, once produced, will travel to the liver via the bloodstream to be converted to its active form, T3, Triiodothyronine to stimulate energy production so that the liver can perform detoxification and other metabolic functions.
What is the hypothalamus?
A very small, cone-shaped gland within the brain.
Its job is to read and interpret hormone levels within the blood and nervous system.
How does the hypothalamus work?
In response to the messages it receives from the blood & nervous system, it produces and secretes certain neurohormones and then delivers those messages directly to the pituitary gland.
You can think of the hypothalamus as the big boss CEO to the entire endocrine system.
What is the hypothalamus’s primary role?
To maintain homeostasis.
How does the hypothalamus maintain homeostasis?
By secreting certain hormonal messages at a faster or slower pace depending upon what external cue it’s receiving (either releasing or inhibiting hormone to help start or stop hormone production further down the line)
What is GHRH/GHIH?
Growth Hormone-Releasing Hormone / Growth Hormone Inhibiting Hormone
Stimulates the release of growth hormone or inhibits it
What is TRH?
Thyrotropin-Releasing Hormone
Stimulates the pituitary to communicate with the thyroid
What is PRH/PIH?
Prolactin-Releasing Hormone/Prolactin Inhibiting Hormone
Stimulates the release of prolactin or inhibits it
What is CRH?
Corticotropin-Releasing Hormone
Stimulates the pituitary to communicate to the adrenals
What is GnRH?
Gonadotropin-Releasing Hormone
Stimulates the pituitary to communicate with the gonads
What role does the pituitary play?
It’s like the middleman or the primary supervisor. Although the hypothalamus is in contro, it can’t do much without the pituitary’s help.
What is the pituitary gland?
It is located just below the hypothalamus within the brain and is divided into two distinct lobes: the anterior pituitary and the posterior pituitary.
If there’s a disconnection between the communication of the hypothalamus and pituitary what can happen?
It can lead to hormones lost in translation and various imbalances and complications.
What hormones does the pituitary produce?
- GH: Growth Hormone in response to GHRH or GHIH
- PRL: Prolactin in responses to PRL or PIH
- TSH: In response to TRH
- ACTH: Adrenocorticotropic hormone in response to CRH
- LH: Luteinizing Hormone
- FSH: Follicle stimulating hormone in response to GnRH
What is the posterior pituitary?
Considered the neuronal lobe as it stores certain hormones produced in the hypothalamus and secretes them upon demand.
What is the anterior pituitary?
Considered to be a glandular lobe because it produces and secretes hormones directly
Do the hromones that are delivered from the hypothalamus to the pituitary reach the full circulatory system?
No they never reach it, they are directly connected between the hypophyseal portal system.
What are the Anterior pituitary hormones and their target tissues?
- ACTH - delivered to the adrenal glands
- TSH - delivered to the thyroid
- GH - delivered to the bone, muscles, and other various tissues
- PRL - delivered to the breast tissue after childbirth
- LH & FSH - delivered to the ovaries to facilitate ovulation
What are the posterior pituitary hormones and their target tissues?
- ADH - anti-diuretic hormone which is delivered to the kidney, to tell it how much water to conserve
- OXT: Oxytocin
What is the pineal gland?
It resembles a small pine cone. Its main job is to control the body’s circadian rhyth, which is the wake and sleep cycle.
How is melatonin produced?
In response to light exposure to the retinas.
When is melatonin suppressed?
In exposure to light, specifically the blue light spectrum from sunlight, LED and fluorescnet lightings.
What is the Cortisol Awakening Response?
The blue light is emitted from the sun first thing in the morning which stimulates our bodies to wake us up.
When the sun goes down, cortisol is decreased, and melatonin takes over, completing the circadian rhythm.
When one hormone is up, the other is down.
Is melatonin a powerful free radical scavenger and anti-inflammatory hormone?
Yes. at night melatonin is working hard to promote inflammation balance and reduce tissue damage from oxidative stress.
Where is melatonin produced?
Within the Pinealocytes, the primary cells located in the pineal gland from the conversino of the neurotransmitter Serotonin.
How is Serotonin produced?
From the essential amino acid, Trypotophan, commonly found in animal-based proteins and complex carbohydrates.
How much of serotonin production occurs within the gut?
95%, as serotonin acts as an important regulator of the migrating motor complex.
The production of melatonin is heavily influenced by what?
Trypotophan, Serotonin, and B vitamins
Digestive issues and nutrient deficinecies in these areas may decrease one’s ability to properly produce melatonin which can lead to cortisol dominance, impacting sleep quality and perpetuating oxidative damange.
What is the Thyroid Gland?
A butterfly-shaped gland located along the windpipe.
What is the thyroid’s primary job?
To regulate metabolism, which is the process of producing energy within cells from the food that we consume
Facilitating growth and development, aiding in protein synthesis and maintaining mineral balance, specifically with the minerals Calcium and Iodine.
Where is thyroid hormone produced?
Between the follicular epithelial cells and the colloid (also known as the lumen) of the thyroid gland
How long is thyroid hormone stored?
Roughly 3 months until stimulated by Thyroid-Stimulating Hormone or TSH from the pituitary.
What plays a major role in calcium regulation with the parathyroid?
Calcitonin is produced in the parafollicular cells aka the “C cells” within the thyroid
What is thyroid hormone produced from?
A combination of the amino acid tyrosine and the mineral iodine.
How much does the thyroid produce?
About 90% inactive T4 (Thyroxine) and 10% active T3 (Triiodothyronine).
What does the T in the thyroid hormone demonstrate?
How many iodine atoms are present.
How many iodine atoms are present in the inactive version of thyroid hormone?
4
In order to activate the thyroid hormone to T3, what needs to happen?
An iodine atom must be removed.
80% of this process occurs within the liver, kidneys, and brain, as well as within every cell of the body.